- ID:
- ivo://CDS.VizieR/J/AJ/162/210
- Title:
- Transit Time Vartiations (TTVs) of WASP-43
- Short Name:
- J/AJ/162/210
- Date:
- 15 Mar 2022
- Publisher:
- CDS
- Description:
- WASP-43b is one of the most important candidates for detecting an orbital decay. We investigate pieces of evidence for this expectation as variations in its transit timings, based on the ground and space observations. The data set includes the transit observations at the TUBITAK National Observatory of Turkey and Transiting Exoplanet Survey Satellite (TESS). We present a global model of the system, based on the most precise photometry from space, ground, and archival radial velocity data. Using the homogenized data set and modeled light curves, we measure the mid-transit times for WASP-43b. Our analysis agrees with a linear ephemeris for which we refine the light elements for future observations of the system. However, there is a negative difference between the transit timings derived from TESS data in two sectors (9 and 35) and a hint of an orbital period decrease in the entire data set. Both findings are statistically insignificant due to the short baseline of observations, which prevents us from drawing firm conclusions about the orbital decay of this ultra-short-period planet. However, assuming the effect of this decrease of the period in the planet's orbit, we derive a lower limit for the reduced tidal quality factor as Q*'>(4.01{+/-}1.15)x10^5^ from the best-fitting quadratic function. Finally, we calculate a probable rotational period for this system as 7.52days from the out-of-transit flux variation in the TESS light curves due to spot modulation.
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- ID:
- ivo://CDS.VizieR/J/AJ/158/133
- Title:
- Transit timing and light curves for K2-146
- Short Name:
- J/AJ/158/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- K2-146 is a mid-M dwarf (M_*_=0.331+/-0.009 M_{sun}_; R_*_=0.330+/-0.010 R_{sun}_), observed in Campaigns 5, 16, and 18 of the K2 mission. In Campaign 5 data, a single planet was discovered with an orbital period of 2.6 days and large transit timing variations due to an unknown perturber. Here, we analyze data from Campaigns 16 and 18, detecting the transits of a second planet, c, with an orbital period of 4.0 days, librating in a 3:2 resonance with planet b. Large, anticorrelated timing variations of both planets exist due to their resonant perturbations. The planets have a mutual inclination of 2.40{deg}+/-0.25{deg}, which torqued planet c more closely into our line of sight. Planet c was grazing in Campaign 5 and thus missed in previous searches; it is fully transiting in Campaigns 16 and 18, and its transit depth is three times larger. We improve the stellar properties using data from Gaia DR2 (Cat. I/345), and use dynamical fits to find that both planets are sub-Neptunes: their masses are 5.77+/-0.18 and 7.50+/-0.23 M_{Earth}_, and their radii are 2.04+/-0.06 and 2.19+/-0.07 R_{Earth}_, respectively. These mass constraints set the precision record for small exoplanets (a few gas giants have comparable relative precision). These planets lie in the photoevaporation valley when viewed in Radius-Period space, but due to the low-luminosity M-dwarf host star, they lie among the atmosphere-bearing planets when viewed in Radius-Irradiation space. This, along with their densities being 60-80% that of Earth, suggests that they may both have retained a substantial gaseous envelope.
- ID:
- ivo://CDS.VizieR/J/ApJS/208/22
- Title:
- Transit timing variation for 12 planetary pairs
- Short Name:
- J/ApJS/208/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extract transit timing variation (TTV) signals for 12 pairs of transiting planet candidates that are near first-order mean motion resonances (MMR), using publicly available Kepler light curves (Q0-Q14). These pairs show significant sinusoidal TTVs with theoretically predicted periods, which demonstrate these planet candidates are orbiting and interacting in the same system. Although individual masses cannot be accurately extracted based only on TTVs because of the well-known degeneracy between mass and eccentricity, TTV phases and amplitudes can still place upper limits on the masses of the candidates, confirming their planetary nature. Furthermore, the mass ratios of these planet pairs can be relatively tightly constrained using these TTVs. The planetary pair in KOI 880 seems to have particularly high mass and density ratios, which might indicate very different internal compositions of these two planets. Some of these newly confirmed planets are also near MMR with other candidates in the system, forming unique resonance chains (e.g., KOI 500).
- ID:
- ivo://CDS.VizieR/J/ApJS/210/25
- Title:
- Transit timing variation for 15 planetary pairs. II.
- Short Name:
- J/ApJS/210/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Following on from Paper I (Cat. J/ApJS/208/22) in this series, I report the confirmation of a further 30 planets in 15 multiple-planet systems via transit timing variations (TTVs), using the publicly available Kepler light curves (Q0-Q16). All 15 pairs are near first-order mean motion resonances, showing sinusoidal TTVs consistent with theoretically predicted periods, which demonstrate they are orbiting and interacting in the same systems. Although individual masses cannot be accurately extracted based only on TTVs (because of the well known degeneracy between mass and eccentricity), the measured TTV phases and amplitudes can still place relatively tight constraints on their mass ratios and upper limits on their masses, which confirm their planetary nature. Some of these systems (KOI-274, KOI-285, KOI-370, and KOI-2672) are relatively bright and thus suitable for further follow-up observations.
- ID:
- ivo://CDS.VizieR/J/A+A/555/A92
- Title:
- Transit timing variations on Qatar-1
- Short Name:
- J/A+A/555/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Variations in the timing of transiting exoplanets provide a powerful tool detecting additional planets in the system. Thus, the aim of this paper is to discuss the plausibility of transit timing variations on the Qatar-1 system by means of primary transit light curves analysis. Furthermore, we provide an interpretation of the timing variation. We observed Qatar-1 between March 2011 and October 2012 using the 1.2m OLT telescope in Germany and the 0.6m PTST telescope in Spain. We present 26 primary transits of the hot Jupiter Qatar-1b. In total, our light curves cover a baseline of 18 months. We also refine the ephemeris of Qatar-1b, which we find to be T0=2456157.42204+/-0.0001BJD_TDB_ and P=1.4200246+/-0.0000007 days, and improve the system orbital parameters.
- ID:
- ivo://CDS.VizieR/J/AJ/159/239
- Title:
- Transmission Spectroscopy Metric of exoplanets
- Short Name:
- J/AJ/159/239
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent years have seen increasing interest in the characterization of sub-Neptune-sized planets because of their prevalence in the Galaxy, contrasted with their absence in our solar system. HD97658 is one of the brightest stars hosting a planet of this kind, and we present the transmission spectrum of this planet by combining four Hubble Space Telescope transits, 12 Spitzer/IRAC transits, and eight Microvariability and Oscillations of Stars Telescope (MOST) transits of this system. Our transmission spectrum has a higher signal-to-noise ratio than those from previous works, and the result suggests that the slight increase in transit depth from wavelength 1.1-1.7{mu}m reported in previous works on the transmission spectrum of this planet is likely systematic. Nonetheless, our atmospheric modeling results are inconclusive, as no model provides an excellent match to our data. Nonetheless, we find that atmospheres with high C/O ratios (C/O~>0.8) and metallicities of ~>100 solar metallicity are favored. We combine the mid-transit times from all of the new Spitzer and MOST observations and obtain an updated orbital period of P=9.489295{+/-}0.000005, with a best-fit transit time center at T0=2456361.80690{+/-}0.00038(BJD). No transit timing variations are found in this system. We also present new measurements of the stellar rotation period (34{+/-}2days) and stellar activity cycle (9.6yr) of the host star HD97658. Finally, we calculate and rank the Transmission Spectroscopy Metric of all confirmed planets cooler than 1000K and with sizes between 1R_{Earth}_ and 4R_{Earth}_. We find that at least a third of small planets cooler than 1000K can be well characterized using James Webb Space Telescope, and of those, HD97658b is ranked fifth, meaning that it remains a high-priority target for atmospheric characterization.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A100
- Title:
- Transmission spectroscopy of HAT-P-32b
- Short Name:
- J/A+A/590/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained low-resolution, multi-object spectra of the planet host star HAT-P-32 and multiple comparison stars during a transit event of HAT-P-32b. The spectral flux was binned in 62 narrow channels from 3300 to 10000{AA} and used to create differential photometric light curves. These light curves were analysed for a wavelength dependence of the effective planetary radius.
- ID:
- ivo://CDS.VizieR/J/A+A/650/A138
- Title:
- TRAPPIST-1 analogue stars TESS light curves
- Short Name:
- J/A+A/650/A138
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- As more exoplanets are being discovered around ultracool dwarfs, understanding their magnetic activity - and the implications for habitability - is of prime importance. To find stellar flares and photometric signatures related to starspots, continuous monitoring is necessary, which can be achieved with spaceborn observatories like the Transiting Exoplanet Survey Satellite (TESS). We present an analysis of TRAPPIST-1 like ultracool dwarfs with TESS full- frame image photometry from the first two years of the primary mission. A volume-limited sample up to 50pc is constructed consisting of 339 stars closer than 0.5mag to TRAPPIST-1 on the Gaia colour-magnitude diagram. The 30-min cadence TESS light curves of 248 stars were analysed, searching for flares and rotational modulation caused by starspots. The composite flare frequency distribution of the 94 identified flares shows a power law index similar to TRAPPIST-1, and contains flares up to E_TESS_=3*10^33^erg. Rotational periods shorter than 5 days were determined for 42 stars, sampling the regime of fast rotators. The ages of 88 stars from the sample were estimated using kinematic information. A weak correlation between rotational period and age is observed, which is consistent with magnetic braking.
- ID:
- ivo://CDS.VizieR/J/MNRAS/497/3790
- Title:
- TRAPPIST-South UCD Transit Survey
- Short Name:
- J/MNRAS/497/3790
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We conducted a global analysis of the TRAPPIST Ultra-Cool Dwarf Transit Survey - a prototype of the SPECULOOS transit search conducted with the TRAPPIST-South robotic telescope in Chile from 2011 to 2017 - to estimate the occurrence rate of close-in planets such as TRAPPIST-1b orbiting ultra-cool dwarfs. For this purpose, the photometric data of 40 nearby ultra-cool dwarfs were reanalysed in a self-consistent and fully automated manner starting from the raw images. The pipeline developed specifically for this task generates differential light curves, removes non-planetary photometric features and stellar variability, and searches for transits. It identifies the transits of TRAPPIST-1b and TRAPPIST-1c without any human intervention. To test the pipeline and the potential output of similar surveys, we injected planetary transits into the light curves on a star-by-star basis and tested whether the pipeline is able to detect them. The achieved photometric precision enables us to identify Earth-sized planets orbiting ultra-cool dwarfs as validated by the injection tests. Our planet-injection simulation further suggests a lower limit of 10 per cent on the occurrence rate of planets similar to TRAPPIST-1b with a radius between 1 and 1.3 R_{Earth}_ and the orbital period between 1.4 and 1.8d.
- ID:
- ivo://CDS.VizieR/J/A+A/510/A107
- Title:
- TrES-2b multi-band transit observations
- Short Name:
- J/A+A/510/A107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new data set of transit observations of the TrES-2b exoplanet taken in spring 2009, using the 1.2m Oskar-Luehning telescope (OLT) of Hamburg Observatory and the 2.2m telescope at Calar Alto Observatory using BUSCA (Bonn University Simultaneous CAmera). Both the new OLT data, taken with the same instrumental setup as our data taken in 2008, as well as the simultaneously recorded multicolor BUSCA data confirm the low inclination values reported previously, and in fact suggest that the TrES-2b exoplanet has already passed the first inclination threshold (i_min,1_=83.417{deg}) and is not eclipsing the full stellar surface any longer.
